Advanced Trellis-Coded Binary Modulation for Enhanced 6G Coverage Using 8-PSK Constellation

Targeting at extreme uplink coverage scenarios in sixth generation (6G) wireless communications, this paper proposes a novel binary waveform with very low peak-to-average power-ratio (PAPR) and very low out-of-band (OOB) emissions. It uses the discrete Fourier transform spread orthogonal frequency division multiplexing (DFT-s-OFDM) signal model, together with 8-level phase-shift keying (8-PSK) modulation symbol constellation. The proposed approach applies trellis-coding in such a way that sharp phase transitions between consecutive modulation symbols are avoided. This results in greatly reduced PAPR and OOB emissions. Furthermore, while fast Fourier transform (FFT) domain linear filtering based spectrum shaping (FDSS) (with or without bandwidth extension) has been widely considered in recent low-PAPR waveform studies, these elements are not needed in the proposed scheme. In other words, the scheme uses only trellis coding on 8-PSK constellation and plain DFT-s-OFDM process. This results in largely reduced computational complexity compared to existing low-PAPR waveforms. Further enhancement of spectrum localization is achieved by improving the phase continuity of the generated signal, avoiding excessive phase transitions between consecutive transform-precoded OFDM symbols and between each main symbol and its cyclic prefix (CP). Extensive simulation results incorporating a practical, highly nonlinear power amplifier (PA) model are provided to demonstrate the performance and benefits of the proposed approach compared to relevant prior art.